1. Field of the Invention
The present invention generally relates to a turning mechanism, and in particular, to a turning mechanism adapted to a projector for turning a zoom bar of a zoom lens.
2. Description of Related Art
Current projectors project images with high definition and high brightness. Due to reduced price and small volume of the projectors, the projectors have been widely used by public. However, the size of the projected screens and the distance between the projected screen and the projector are always limited by the space of environment. Therefore, the projectors are generally equipped with zoom lenses for adjusting the size and resolution of the projected images.
In order to enable a user to manually adjust a zoom bar of the zoom lens, a zoom ring is slidably disposed around a light axis of the zoom lens on a base that accommodates the zoom lens, and is movably connected to an end of the zoom bar. Further, a stopper is mounted to the base to directly define a range of the zoom ring moving around the light axis, thereby indirectly defining a switching range of the zoom bar. Therefore, the user may switch the zoom bar by manually turning the zoom ring, thereby adjusting the focal length of the zoom lens.
However, in the prior art, the stopper cannot be fastened to the base to slidably dispose the zoom ring on the base only unless the zoom ring, the zoom bar, and the stopper are aligned at the same time, which will increase the difficulty in assembly. Moreover, the base is generally made of Al—Mg alloy, and thus when the zoom ring is slidably disposed on the base, the friction between the plastic zoom ring and the surface of the base will produce unpleasant noises.